Pyrazolones and process of preparing same



Patented Aug. 13, 1940 UNITED STATES PATENT OFFICE PYRAZOLONES AND PROCESS OF PREPARING SAME Max Schmid, Riehen, Switzerland, assignor to the firm Society of Chemical Industry in It has been found that the pyrazolones of the general formula wherein .2 stands for a member of the group consisting of hydrogen, Cl, CH3, OCI-Is and $0311, 1) stands for a member of the group consisting of N02, NI-Iz and NH-acyl, :1: stands for a member of the group consisting of H, CH3, COORz (R2 standing itself for a member of the group con- 'sisting of H, CzHs and CH3) and phenyl, and y stands for hydrogen or CH3, are very valuable products as they permit the manufacture of direct dyeing dyestuffs having new and very valuable properties. Such products may be produced by various methods. It has however been found that they can be produced by a convenient method which proceeds surprisingly easily when starting from amines of the general formula wherein the groups NH2,

.. N. O I H H o and -NO2 stand in another position to one another than in ortho-position, and z and U have the above indicated significance. These products can be easily diazotized and what is entirely surprising, be converted into hydrazines of the general formula wherein the hydrazine residue, the

N-(]Tgroup and the NHz-groups occupy the already indicated positions and z and 12 have again the above indicated significance, by treating them with at 285,441. In Switzerland November 6,

3 Claims. (01.260-310) least 1 mol of a salt of sulfurous acid in a weakly alkaline medium whose pH lies advantageously between '7 and 9 and then with a reducing agent, for example a metal selected from the group consisting of iron and zinc, or also with other agents such as stannous chloride, in an acid medium whose pH lies advantageously between 6.5 and 2. When the first stage of the reduction of the diazocompound has been carried out, viz. the alkaline reduction, wherein a further reducing agent, namely zinc dust, is advantageously added for completing the reaction, there may be obtained in intermediate. stages hydrazines of the general formula wherein the position of the substituents and the meaning of the symbols 2 and u have already been indicated.

Such hydrazines of the general formula have the property that the substituted benzoylamino group is relatively very firmly linked, so that when treated with acid saponifying agents they are converted into hydrazines of the general formula 2 v HaN1TT@ IIT()mNH2 wherein the hydrazine residue, the

and the NHz-groups occupy the already indicated positions and z and u have again the above indicated significance. These new hydrazines can be converted with the most various c-ketone-acid esters or carbonyl acid esters, for instance formylacetic ester, acetoacetic ester, methyl and ethylesters of oxalacetic acid, benzoylacetic ester, terephthaloyl-di-acetic ester, para-chloro-benzoyl acetic ester, into pyrazolones which correspond to the general formula I 2 v C=N \N NC NH2 HnC-C 1 1 g wherein the pyrazolone nucleus, the

NCgrup N' NC Nacyl H I it l l wherein at, z and 21 have the above indicated si nificance. Finally, the products of the first stage of the reduction of the diazotized products of the above explained general formula may be condensed to pyrazolone derivatives with the keto or carbonyl acid esters after splitting off the sulfonic group attached to the hydrazine residue, that is to say to compounds of the general formula wherein the position of the substituents and the meaning of the symbols 2 and 22 have already been explained. All these new pyrazolones are light colored powders which dissolve in dilute caustic alkalies, if desired after addition of some alcohol, to yellow solutions from which they may be precipitated by acidifying. With diazo compounds these pyrazolones yield dyestuffs which, as mentioned above, may be characterized by valuable and hitherto unknown properties.

The following examples illustrate the invention, the parts being by weight:

Example 1 25.7 parts of finely powdered para'-nitrobenzoyl-meta-phenylenediamine of the formula are suspended in 50 parts of water, 30 parts of hydrochloric acid of specific gravity 1.15 and ice. A solution of '7 parts of sodium nitrite in 20 parts of water is entered in drops into this mixture at 0-l0 0., the whole is stirred for one hour, then filtered and the diazonium chloride is washed with a little ice water. The suspension is then stirred with 100 parts of water and poured, while stirring, into a cooled mixture consisting of 65 parts of bisulfite solution of 40 per cent strength, parts of sodium carbonate and 10 parts of caustic soda solution of 36 B. Such a mass has a pH of about 7.5 to 8.5. The mixture is stirred overnight, then heated to 80 C., parts of acetic acid of per cent strength are added thereto and 5 parts of zinc dust are gradually strewn in. The solution becomes light yellow after a short time. It is filtered from the zinc dust in excess and sodium carbonate is added until the solution has a feebly alkaline reaction. By salting out there is obtained the sodium salt of the hydrazine sulfonic acid of the formula NlIO oQ-NOQ which is colored light yellow and is easily soluble in water.

When dissolving 1 part of this sodium hydrazine sulfonate in 10 parts of water of 0., add ing 3 parts of hydrochloric acid of specific gravity 1.15 and stirring the solution for 45 minutes at Gil- C., the hydrochloride of the meta- (para'-nitrobenzoyl)- aminophenyl hydrazine of the formula nn-oo-Qnm is precipitated on cooling as a brown-yellow coarsely grained powder which is also sparingly soluble in hot water.

By reduction of the meta(para-nitrobenzoyl)- aminophenyl hydrazine sulfonic acid of the formula NHO c-Qno z with iron and acetic acid there is obtained the corresponding aminohydrazine sulfonic acid of the formula NHO C-ON 11 This reduction may be effected for instance as follows 35.2 parts of the hydrazine-N-sulfonic acid of the formula Nl[CO--NO:

are gradually introduced in the form of the sodium salt at 75 C. and while vigorously stirring into a mixture rendered active with about 10 parts of acetic acid of 30 per cent strength and consisting of 30 parts of iron and 100 parts of water. When complete decolorization can be ascertained sodium carbonate is added to the reduction liquor .until it reacts alkaline. The whole is filtered hot, i. e., at about -80 C. in order to remove the iron mud and the sodium salt of the hydrazine-N-sulfonic acid of the formula HOaS-NH-NH NH-C o-ONH,

is separated from the filtrate by addition of common salt. This hydrazine-N-sulfonic acid is saponified by dilute hydrochloric acid at -65 C. to the meta-(para-aminobenzoyl)- aminophenylhydrazine of the formula which is easily soluble as hydrochloride and which is isolated by neutralizing the hydrochloric acid solution with sodium carbonate in the cold.

When using instead of para'-nitrobenzoylmeta-phenylenediamine, meta'-nitrobenzoylpara-phenylene diamine, para-nitrobenzoylpara-phenylene diamine or meta'-nitrobenzoylmeta-phenylene diamine, there are obtained similar. products, for example products of the formulas Example 2 33.7 parts of para-nitrobenzoylpara-phenylene-diamine-ortho-sulfonic acid the formula HaN-QNH-C GONG:

are dissolved in 70 parts of water and 12 parts of caustic soda solution of 36 B. to which are added '7 parts of sodium nitrite. This solution is poured into a mixture of 42 parts of hydrochloric acid of specific gravity 1.15 and so much ice that the temperature does not exceed 10 C. The Whole is stirred for a further hour at 0-l0 0., and then filtered. The diazonium chloride thus obtained is suspended in 100 parts of ice water and the suspension is poured into a cooled mixture consisting of parts of bisulfite solution of 40 per cent. strength, 16 parts of sodium carbonate and 10 parts of caustic soda solution of 36 B. The whole is stirred overnight, then heated to 80 C., 25 parts of acetic acid of 30 per cent strength are added thereto and 5 parts of zinc dust are gradually strewn in until the color of the solution changes to yellow. The hydrazine sulfonic acid of the formula HOgS-NH-NH-QNH-O C-ONO,

Horas is obtained from the filtered solution by salting out.

By heating With dilute hydrochloric acid the hydrazine sulfonic acid is saponified to the hydrazine of the formula HaN-NH-QNH-C oONo,

Hon

When reducing the nitrohydrazine sulfonic acid of the formula Q-NH-Q 0-6-1101 HOaS with iron and acetic acid in the manner indicated above, the corresponding aminohydrazine sulfonic acid of the formula HOaS is obtained, which is converted into the hydrochloride of the hydrazine of the formula mN-NH-Ormc CONE:

or in Example 2 the par'a'-nitrobenzoyl-paraphenylene-diamine-ortho-sulfonic acid by the corresponding sulfonic acids of the formula CHI the following hydrazines may be obtained over the N-sulfonic acids:

Example 3 27.7 parts of finely powdered 1-(para-nitrobenzoyl)-amino-4-amino-3-chlorobenzene of the formula are suspended in 100 parts of water, 30 parts of hydrochloric acid of specific gravity 1.15 and ice. An aqueous solution of 7 parts of sodium nitrite is added to this mixture at 5-10 C, and the Whole is stirred until diazotization is complete.

The diazo paste is added while stirring to an ice cooled mixture consisting of parts of bisulfite solution of 40 per cent strength and 15 parts of sodium carbonate, care being taken that the action of the sulfite on this diazo compound takes place always in a medium of a pH 'of about '7 to 8.5. The mixture is stirred overnight, heated to -80 C. and salted out. The yellow precipitate which has separated is suspended in about 100 parts of water of 0., about 20 parts of acetic acid of 30 per cent strength are added to this mixture and zinc dust is gradually strewn in until it is of light yellow color. The mixture is filtered to remove the zinc dust in excess, and sodium carbonate is added until the solution has a feebly alkaline reaction whereupon the N-sulfonic acid of the formula is salted out as sodium salt.

When introducing the same at about 60 C. into a mixture of iron filings and water rendered caustic with some hydrochloric acid or acetic acid, and stirring the mixture until it is completely decolorized, adding sodium. carbonate until the reduction liquor reacts clearly alkaline, filtering the whole to remove the iron mud and salting out the filtrate, there is obtained the 1- (4-'aminobenzoylamino) -4-hydrazino-N-sulfo-3- chlorobenzene of the formula in the form of the sodium salt.

When carefully treated with acids, for example hydrochloric acid, at 70-80 C., the N-sulfogroup is split off with formation of the salt of the hydrazine of the formula Example 4 33.? parts of meta-nitrobenzoyl-para-phenylene-diamine-ortho-sulfonic acid of the formula are dissolved in 60 parts of caustic soda solution of 36 B. and 120 parts of water, to which are then added '7 parts of sodium nitrite. This solution is poured into a mixture of parts of hydrochloric acid of specific gravity 1.15 and so much ice that the temperature does not exceed 5 C. The diazonium salt is filtered after 1 hour, suspended in 150 parts of ice water and poured into a cooled mixture consisting of 65 parts of sodium bisulfite of 40 per cent strength, 10 parts of caustic soda solution of 36 B., 20 parts of sodium carbonate and parts of Water. The whole is stirred overnight at 0-5 C. whereupon it is heated to 60 C. and 30 parts of hydrochloric acid of specific gravity 1.15 are added thereto so that the solution reacts very feebly acid to Congo. The solution is then gradually poured into a mixture consisting of 30 parts of iron in 100 parts of water and 10 parts of acetic acid of 30 per cent strength, the temperature amounting to about 60 C. After complete decclorization there are added 15 parts of sodium carbonate and the whole is filtered to remove the iron mud. In the solution exists the sodium salt of the hydrazine-N-sulfonic acid of the formula For saponification the solution is heated to 60 C. and mixed with 180 parts of hydrochloric acid of specific gravity 1.15 so that an acid of about 5 per cent strength is formed. This is stirred for /2 hour at 60-65 C. On cooling the hydrazine of the formula crystallizes as hydrochloride.

Example 5 30.8 parts of the para-(para-nitrobenzoy1) aminophenyl-hydrazine of Example 1 are dissolved in the heat in parts of alcohol and 53 parts of sodium carbonate solution of 10 per cent strength. To this solution are added 10 parts of acetic acid of 30 per cent strength and 13 parts of acetoacetic ester and the whole is heated for one hour to feebly boiling. It is then filtered and the solution is mixed at 6065 C. with 30 parts of caustic soda solution of 36 B. Stirring is continued for a further hour at this temperature and the pyrazolone of the formula CH;C=N\

H2C(fi o is precipitated from the filtered and cooled solution. This pyrazolone can be reduced by sodium sulfide at 80 C. to the corresponding aminopyrazolone of the formula CHa-C=N\ zC|C| o This may be also obtained directly by condensing the aminohydrazine of the formula Example 6 39.5 parts of the hydrazine of Example 2 of the formula are dissolved in 300 parts of water and 16 parts of sodium carbonate. To this solution is added a solution of 21 parts of sodium oxalic acetic ester in 100v parts of water and the whole is stirred for 1 hour to 80 C. 12 parts of caustic soda solution of 36 B. are then added and stirring continued for hour at about 60 C., whereupon the mixture is filtered after cooling. The pyrazolone of the formula may be precipitated by acidifying. If this pyrazolone is heated for 2 hours to 70-80 C. with caustic soda solution of about 10 per cent strength and then allowed to cool, the free pyrazolone carboxylic acid of the formula is precipitated by acidifying.

Example 7 If the disodium salt of the amino-pyrazolone of the formula H0ooc=N 1 HBO-C II SOaH 0 (obtained by condensing the hydrazine of the formula in an aqueous solution w th So um oxalacetic ester, saponifying the pyrazolone carboxylic acid ester and then reducing the nitro-group with sodium sulfide) is dissolved in water, adding in drops to this solution at -15 C. so much acetic acid anhydride that the free amino-group can no longer be detected, and. filtering, there is obtained a pyrazolone of the formula E201? SOaH Instead of acetic acid anhydride there may also be used benzoyl chloride and other acid chlorides or organic halogen compounds having such an action, for instance'chloroformic ester, cyanuric chlorides, arylsulfochlorides and the like.

By using the parent materials indicated in Examples 1 to 4 for the manufacture of the corresponding hydrazines over the hydrazine-N- sulfonic acids, the corresponding pyrazolones can be produced by condensing these hydrazines with the c-ketoor carbonyl-carboxylic acid esters cited for example in Example 5.

Further it is possible first of all to reduce the nitro-group of a nitrophenylhydrazine sulfonic acid to the amino-group, acidylate the latter with the nitroaroyl chlorides and if necessary reduce the nitro-group or eliminate the N-sulfonic group by acid saponifying agents. The course of the reaction is then the following:

HOaSNH-NH N02 H03SNENH- NH:

In the operations described above there may be used as parent compounds inter alia compounds of the following formulas NHr-QNH-o 0- NO:

NHr- NHC O NO:

CHaO- OCH:

I NHr-QNHC 0 NO:

This application is a continuation-in-part of my application Serial No. 108,902, filed Novemher 2, 1936.

What I claim is:

1. The pyrazolones of the general formula wherein the pyrazolone nucleus and the ITI(]'Tgroup hydrogen and CH3, which products are light colored powders capable of dissolving in water on addition of alcohol and caustic alkalies and capable of coupling with diazo-compounds to form azo dyestuffs.

2. The pyrazolones of the general formula wherein :1: stands for a member of the group consisting of H, CH3, COOR, R. standing for a member of the group consisting of H, CH3 and C2H5, one z stands for H and the other 2 stands for a sulfonic group, one '0 stands for H and the other 0 stands for a member of the group consisting of N02, NHz and NH-acyl, and wherein the pyrazolone nucleus and the stand in another position to one another than in ortho-position, which products are light colored powders dissolving in water on addition of caustic alkalies and coupling with diazo-compounds to form azo dyestufis.

3. The product of the formula which is a light colored powder dissolving in water on addition of alkalies and coupling with diazo-compounds to form azo dyestufis.

MAX SCHMID. 

